Way back when I was a grad student who had just started, I went to a career symposium that the homecountry scientific organization organized. It was before it was okay to say that you wanted to leave academia after your defense, so most of it was about manuscript and grant writing, creative thinking, networking and that kind of stuff, but of course a lot of those things are very transferable. I don't remember much of it, but I do remember one very important lesson: "If you want something (i.e. a job), tell as many people as possible, so they know what you want".
This may just be the simplest advice you have ever read, but it is important to keep in the back of your head. If you have a dream, don't keep it to yourself, but share it with whoever you're talking to - as scary as that may seem at first. Because how can people hire you if they don't know that you want the job? How can you use someone's network if you don't know they have these connections? I'm sure many people are willing to help others in their career, as long as they know that that is what you want.
Around the same time I started my new job, 2 other scientists started working there, and we found that the common denominator in us getting these jobs was the fact that we had already had informational interviews and probably the recruitment people got our CVs through multiple channels. So again, telling people that you want the job seems very important.
I think the only people in the world who don't really need this advice are toddlers, who already take it to heart on a daily basis (I WANT ICECREAM NOW!!!!). I guess the rest of our lives should be dedicated to learning how to ask things in a way that doesn't annoy those around us...